Total worldwide usage for Mac OS X for August was recorded as 7.13 percent -- which doesn't seem like much when compared to total Windows usage of 91.77 percent -- but it comfortably beats the 6.15 percent worldwide usage share for Windows Vista.

The slow erosion of the Windows Vista usage share, combined with the similarly slow increase in Mac OS X usage, made the switch inevitable. Windows Vista never gained the widespread popularity -- either in the home or with enterprise users -- that was seen by Windows XP and Windows 7. At the same time Apple has been making slow but consistent progress in getting Macs into more and more homes and businesses, selling some 4 million each and every quarter.

The data also shows how rapidly Apple's latest OS X release -- OS X 10.8 Mountain Lion -- is being adopted by users. In a little over a month -- OS X 10.8 was released June 25 -- the ninth major release of OS X already has a worldwide usage share of 1.34 percent, rapidly closing in on 10.6 Snow Leopard with a share of 2.23 percent, and 10.7 Lion with a 2.29 percent share.

This rapid adoption is down to people upgrading existing Macs as opposed to people rushing out to buy new systems.

Overall though, if we look at the bigger picture, we're not seeing any evidence of any of the operating system players -- Windows, Mac or Linux -- making any significant land grabs in terms of usage share.

NetMarketShare uses data captured from the 160 million unique visitors browsing some 40,000 web sites it monitors for its clients.